Aches come part and parcel with psoriatic arthritis (PsA). Those who have this inflammatory condition often report feeling joint pain in their hips, back, hands, knees, and feet during disease flares. In addition to experiencing these symptoms, roughly 35 percent of people with a psoriatic disease develop enthesitis — inflammation of the connective tissue between tendons or ligaments and bone. This symptom of PsA typically appears soon after PsA onset.

According to the National Psoriasis Foundation, only people with spondyloarthropathies — which include PsA, ankylosing spondylitis, and axial spondyloarthritis — consistently experience enthesitis as a symptom. Other forms of arthritis, like rheumatoid arthritis and osteoarthritis, don’t usually involve enthesitis.

This article will cover the connection between PsA and enthesitis, as well as what you and your rheumatologist can do to manage your symptoms.

What Is Enthesitis?

The human body contains more than 100 entheses, which are the places where tendons or ligaments connect with a bone. They all serve to anchor the soft tissues that bind bones to muscles, ensuring smooth movement. Enthesitis (also referred to as enthesopathy) occurs when an enthesis and its surrounding tissues become inflamed. Once inflammatory arthritis like PsA sets in, enthesitis can cause musculoskeletal pain or limit a person’s ability to move affected body parts.

Enthesitis mainly affects the points at which tendons and ligaments insert into bones. However, research suggests that enthesitis can affect any areas where hard and soft tissues come together, like joint capsules and fascia (connective tissue that surrounds and supports muscles, bones, and organs). Areas affected by enthesitis often become ropy in texture (a condition called fibrosis) or start to solidify through a process called ossification.

Enthesitis in Psoriatic Arthritis

PsA affects roughly one-third of all people with psoriasis. Enthesitis is a relatively common symptom of PsA. In fact, it is one of the hallmarks of PsA, and it’s related to severe disease. Other main signs include:

• Peripheral arthritis, which affects large and small joints in the hips, knees, wrists, elbows, feet, and ankles
• Spondylitis, which stems from inflammation of the spinal or sacroiliac joints, or those connecting the sacrum and pelvis
• Dactylitis, also known as sausage digits, which causes swelling in the fingers and toes

If you have psoriasis and you’re noticing these symptoms, it might be a sign of PsA.

Symptoms of Enthesitis

Enthesitis often causes pain and limits movement (stiffness) in the affected joints. People with enthesitis often experience aches in their feet, knees, elbows, hips, and shoulders, although enthesis usually only affects one or two locations at a time.

Although enthesitis can affect any enthesis, it most commonly appears at:

• The Achilles tendon, which runs down the back of the heel
• The lateral epicondyles, the bony bump on the outside of the elbow
• The plantar fascia, the ligament connecting the heel to the front of the foot

As one MyPsoriasisTeam member shared, “My worst enthesitis is in my feet. I can’t be on my feet long, let alone walk very far.”

In severe cases, chronic (long-term) inflammation can cause bone spurs to form near the enthesis or within nearby ligaments. People with PsA and enthesitis may also notice pitting — small depressions — in their fingernails or toenails, or they may experience onycholysis, which is when the nails start to lift away from the nail bed.

Does Psoriatic Arthritis Cause Enthesitis?

PsA is not the sole, or even a direct, cause of enthesitis. For reasons that doctors don’t yet fully understand, people with PsA tend to have a lower threshold for enthesitis development. Mechanical stress, injury, or infection can all trigger long-term inflammation and ultimately lead to full-blown enthesitis. Enthesitis affects more than one-third of people with PsA. Doctors believe enthesitis is better described as an early sign of PsA, rather than a direct result of the disease.

Research indicates that enthesopathy is heavily involved in the development of PsA. Enthesitis tends to correlate with worse health outcomes in people who have PsA. One study found that up to 52 percent of people with PsA-related enthesitis have moderate to severe PsA, compared to just 23 percent of those who don’t have enthesitis. People with enthesitis were also more likely to experience other PsA symptoms such as nail psoriasis and dactylitis.

There are several risk factors associated with PsA-related enthesitis. Those who have enthesitis in PsA tend to be young, have severe cases of PsA, or have a high body mass index (BMI).

People who don’t have PsA can also develop enthesitis, typically after they have experienced an injury or repetitive trauma. Lateral epicondylitis (tennis elbow), for example, is a common enthesitis-related complaint that occurs after a person overuses their elbow with repetitive movements.

The main difference between enthesitis caused by mechanical (physical) problems and PsA-related enthesitis is that PsA enthesitis over time affects multiple entheses persistently, while mechanical enthesitis is caused by a single injury that can heal. Generally speaking, enthesitis that’s related to overuse will fade if a person cares for their injury and avoids the repetitive movement that caused their inflammation. But for a person with PsA, enthesitis is often a chronic problem.

Diagnosing Enthesitis in Psoriatic Arthritis

If you have psoriasis on your skin and start to feel pain in your feet, elbows, or hands, you should talk to your doctor immediately about the possibility of PsA. Delaying the diagnosis and treatment of PsA by even six months could lead to permanent joint damage and a substantially lower quality of life.

Diagnosing enthesitis is relatively straightforward most of the time. Your doctor will likely consider your medical history and symptoms. If you have psoriasis and nail pitting and are experiencing pain in a telltale location — such as your Achilles tendon — your doctor might be able to make their baseline diagnosis without further testing.

However, there are some situations when your condition might not be as easy to define. For example, fibromyalgia can cause pain similar to enthesitis pain. To make a differential diagnosis (distinguishing between two or more conditions that have similar symptoms to determine the correct one), your doctor might conduct a few physical tests, such as moving your affected limb, or they may order an ultrasound to check for signs of enthesitis.

Treatments for People With Psoriatic Arthritis

It’s important that you start exploring treatment options for PsA right away to prevent permanent joint damage. It’s also important because having enthesitis is linked to increased disease burden for people with PsA. The approach your doctor recommends will usually depend on the severity of your condition. Some mild cases can even be handled with nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil), but other cases may need biologics or steroids.

Biologics

Biologic therapies are made from living organisms that help treat certain diseases by targeting the immune system. If NSAIDs aren’t sufficient, your rheumatologist might suggest biologic therapies. These may include:

• Adalimumab (Humira)
• Secukinumab (Cosentyx)
• Infliximab (Remicade)
• Risankizumab-rzaa (Skyrizi)

Steroids

Local corticosteroid injections (steroids) may reduce disease activity and pain in people with PsA and enthesitis. However, steroids should be used carefully, as they may cause side effects.

Corticosteroids can work quickly for some people. One MyPsoriasisTeam member wrote that prednisone has been “like an absolute wonder drug!” They added, “It takes away almost all of the pain and most of the stiffness, too. I can actually sleep much better and get up without any hesitation in the morning and carry on my life pretty much as I used to.” Keep in mind that systemic oral corticosteroids reduce inflammation throughout the body but can have side effects.

Other Treatments

In addition to the medications mentioned above, your doctor may prescribe oral systemic medications, including:

• Apremilast (Otezla), a type of medication called a PDE4 inhibitor
• JAK inhibitors such as tofacitinib (Xeljanz)

Meet Your Team

MyPsoriasisTeam is the social network for people with psoriasis and psoriatic arthritis and their loved ones. Here, more than 123,000 members come together to ask questions, give advice, and share their stories with others who understand life with psoriasis and psoriatic arthritis.

Do you experience enthesis? What has or has not worked in managing it? Share your experiences in the comments below or by posting on your Activities page.